• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.5C
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• pp.706-715
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• 2004

In this paper, to decide the watermark embedding positions and embed the watermark we use the subband tee structure which is presented in the wavelet domain and the edge information in the spatial domain. The significant frequency region is estimated by the subband searching from the higher frequency subband to the lower frequency subband. LH1 subband which has the higher frequency in tree structure of the wavelet domain is divided into 4${\times}$4 submatrices, and the threshold which is used in the watermark embedding is obtained by the blockmatrix which is consists by the average of 4${\times}$4 submatrices. Also the watermark embedding position, Keymap is generated by the blockmatrix for the energy distribution in the frequency domain and the edge information in the spatial domain. The watermark is embedded into the wavelet coefficients using the Keymap and the random sequence generated by LFSR(Linear feedback shift register). Finally after the inverse wavelet transform the watermark embedded image is obtained. the proposed watermarking algorithm showed PSNR over 2㏈ and had the higher results from 2％ to 8％ in the comparison with the previous research for the attack such as the JPEG compression and the general image processing just like blurring, sharpening and gaussian noise.

• Journal of the Korea Concrete Institute
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• v.25 no.3
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• pp.347-354
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• 2013

Recently, crushed fine aggregates are being widely used due to the shortage of natural sand. In Korea, the amount of fine particles under 0.08 mm contained in crushed fine aggregates is restricted to be less than 7%, which is similar to the regulations of ASTM but is still very strict compared to the regulations of the other nations. In addition, the crushed aggregates already have in them about 20% of fine particles under 0.08 mm which occurs while they are crushed. The fine particles are not easy to wash out, and also to maximize the use of resources it is deemed necessary to review the possibility of enhancing the limit of the amount of fine particles. Therefore, this study conducted experiments to analyze the characteristics of fine particles under 0.08mm and their influence on the properties of concrete. Experiments using silt and cohesive soil were also done for comparison. In the experiments on fine particles, the methylene blue value was more in the soil dust contained in silt and cohesive soil than in the stone powder contained in crushed fine aggregates. Also, the methylene blue value had a close correlation with packing density and liquid & plastic limit. In the experiments done with concrete, the quantity of high range water reducing agent demanded to obtain the same slump increased as the fine particle substitution rate heightened. However, in the experiment which used stone powder testing the compressive strength and tensile strength of concrete in the same water-cement ratio, there was little change in strength with less than 20% addition of fine particles among the fine aggregates, and no meaningful difference in the amount of drying shrinkage of concrete.

• Smart Media Journal
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• v.1 no.3
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• pp.36-42
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• 2012

Recently, the smart applications, such as smart phone and smart TV, become a hot issue in IT consumer markets. In particular, the smart TV provides 3D video services, hence efficient coding methods for 3D video data are required. Three-dimensional (3D) video involves stereoscopic or multi-view images to provide depth experience through 3D display systems. Binocular cues are perceived by rendering proper viewpoint images obtained at slightly different view angles. Since the number of viewpoints of the multi-view video is limited, 3D display devices should generate arbitrary viewpoint images using available adjacent view images. In this paper, after we explain a view synthesis method briefly, we propose a new algorithm to compensate view synthesis errors around object boundaries. We describe a 3D warping technique exploiting the depth map for viewpoint shifting and a hole filling method using multi-view images. Then, we propose an algorithm to remove boundary noises that are generated due to mismatches of object edges in the color and depth images. The proposed method reduces annoying boundary noises near object edges by replacing erroneous textures with alternative textures from the other reference image. Using the proposed method, we can generate perceptually inproved images for 3D video systems.

• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.1
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• pp.26-33
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• 2014

The study investigates the effects of the type, replacement ratio and method of use of mineral admixtures on the fluidity, bleeding ratio, volumetric change and compressive strength of the grout in order to provide basic data for the development of high-quality grout for PSC bridges. In view of the results relative to the type and replacement ratio of the mineral admixtures, it appears that fly ash has practically no effect on the improvement of the fluidity nor on the reduction of bleeding and shrinkage of the grout. On the contrary, blast furnace slag and silica fume appear to have significant effect on the improvement of the fluidity or on the reduction of bleeding and shrinkage of the grout. With regard to the combined use of mineral admixtures, the combination of fly ash and blast furnace slag provides satisfactory fluidity but with significant increase of bleeding and shrinkage, whereas the combination of blast furnace slag and silica fume reduces bleeding and shrinkage but with large loss of the fluidity. On the other hand, the combination of fly ash and silica fume results in satisfactory fluidity accompanied with fair reduction of bleeding and shrinkage of the grout. In view of these results, the type, replacement ratio and method of use of the mineral admixtures are seen to influence the fluidity, bleeding and volumetric change of the grout. Accordingly, it is necessary to select the mineral admixtures considering these effects for their exploitation in the grout of PSC bridges.

• Magazine of the Korea Concrete Institute
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• v.4 no.1
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• pp.119-126
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• 1992

AC] 318-H9 Recommended that when the specified compressive strength of concrete in a column is greater than 1. 4 times that specified for a floor system, top surface of the colurrm concrete shall extend 2ftU;OOrrun) into the slab from the face of colUlml to avoid unexpected brittle failure. The purpose of this investigation is to suggest the basic information for the structural safety, The major variables are com preSSlve strength of concrete, shear confinement ratio, and loading types. The test results showed that the load capaCIty of speCImen subjected to monotOI1lC loading had more than that of specimen subjected to one way cyclic loading. The failure modes of specimens under cyclic loading were concentrated at 5-20cm apart region from beam-column joint face and ductility index are increased with increasing of shear confinement ratio. Keywords: ACI 318-89, High and Low Strength Concrete, Beam-Column Joint, Shear Confinement Ratio, Loading Type, Ductility Index, Extension Distance.

• Resources Recycling
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• v.21 no.6
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• pp.12-22
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• 2012

This study investigated a utilization technology of light burned dolomite. light burned dolomite ($CaMg(CO_3)_2$) generated in furnace (steel manufacturer) is an alternative to quick lime. Using light burned dolomite has an effect on reducing the consumption of fluorite slag MgO concentration in supersaturated solution by prolonging the life of softening effect. Armophous MgO, not containing periclase is formed by firing dolomite under $800^{\circ}C$. It has larger surface area and higher reactivity than periclase, and also shows better expansion effect than quicklime. Due to those effects, therefore, armophous MgO produced from light burned dolomite is used as an alternative expansion agent in mortar. In the experiment, characteristics of light burned dolomite were compared to those of existing expansion agents such as anhydrite and quicklime. Then, each expansion and shrinkage rates were measured over a period of about 3 months in both of 1m Jis mold at labscale and apartment mortar flooring at field scale. In the result, it was observed that light burned dolomite in mortar flooring more compensates for the expansion and shrinkage rates than the existing expansion agents, showing low expansion rate of below 0.05% and also decreases the crack.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.2
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• pp.68-75
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• 2018

In this study, to solve the problems of the conventional crack repair and injection method, high elasticity latex was used as the material of the storage tube to withstand the high pressure in the center part differently from the general port. When the repair solution was injected into the crack part, The TPS method was developed so that the air existing in the TPS can be discharged. In addition, a new infusion port in which a valve blocking the backflow of the remediation solution was installed at the injection port was developed and the physical characteristics of the port were analyzed. As a result of the evaluation, it was found that the filling rate of the remedial solution was improved compared to the existing ordinary injector method, and the cracks were completely filled in the test conditions. Compressive strength and tensile strength after repair showed about 20% decrease after repair in case of using ordinary injector method, while TPS method showed about 2~7% increase after repair. The results of this study showed that the injection port method using the elastic storage tube increased the injection performance and the quality after repair compared to the conventional injector method. The result of this study is expected to be utilized as the basic data for application and commercialization of the result to the practical structure.

• Journal of the Korean Geosynthetics Society
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• v.22 no.1
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• pp.87-96
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• 2023

There are a lot of difference between the surface settlement and the differential settlement measured at the Busan New Port, where the dredged and reclaimed clay layer exists and below the clay is originally thickly distributed. To find the cause and solution of this, the actual conditions of each differential settlement used for the soft ground improvement, characteristics, installation method, measurement frequency, measurement data management, and data analysis of each type were considered. In the deep soft ground improvement work where large deformation occurs, the bending deformation of the screw-type differential settlement gauge is less than that of other types of measuring instruments, so there is less risk of loss, and the reliability of data is relatively high as the instruments are installed by drilling for each stratum. Since the greater the amount of high-precision settlement measurement data, the higher the settlement analysis precision. It is necessary to manage with higher criteria than the measurement frequency suggested in the standard specification. For the data management of the differential settlement gauge, it is desirable to create graphs of the settlement and embankment height of the relevant section over time, such as surface, differential, and settlement of pore water pressure gauge for each point. In the case of multi-layered ground with different compression characteristics, it is more appropriate to perform settlement analysis by calculating the consolidation characteristics of each stratum using a differential settlement data.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.12a
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• pp.69-69
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• 2020

소엽(Perilla frutescens var. acuta)은 흔히 차조기, 자소엽 등으로 불리며, 식재료나 약재로 이용된다. 최근 들어 자소엽을 향장 원료로 활용하고자 하는 시도가 이루어지고 있다. 따라서 유기자재 처리를 통해 향장원료 자소엽의 고품질 생산을 위하여 본 시험을 실시하였다. 전북 농업기술원 허브산채시험장에서 육묘한 종묘를 2020년 5월 노지 포장에 주간 간격 50cm 한줄 재배로 정식하였다. 처리는 규산염(성분량 20%), 키토산(성분량 5%)가 함유된 자재를 각각 500배, 1,000배 희석하여 6월 21일, 8월 3일, 8월 23일 총 3회에 걸쳐 압축 분무기를 이용해 작물이 충분히 적셔지도록 살포하였으며, 무처리구는 물을 살포하였다. 초장, 초폭, SPAD, 생체중, 건물중을 조사하였으며 잎과 꽃의 총 폴리페놀 함량, 총 플라보노이드 함량, FRAP(철환원 항산화력) 활성 ABTS+ 라디칼 저해활성을 측정하였다. 생육특성 중 초장과 초폭은 처리간 유의성은 없었으나 무처리, 규산염 500배, 키토산 1,000배 처리에서 대체로 높았으며, SPAD는 키토산 1,000배가 가장 양호하였다. 수량성은 모든 자재 처리구가 무처리구보다 많았으며, 지상부 생체중은 무처리 대비 키토산 1,000배는 14.1%, 건물중은 무처리 대비 11.9%로 키토산 1,000배 처리가 수량성이 가장 많았다. 총 폴리페놀 함량은 꽃보다 잎에서 더 높은 수치로 나타났으며, 잎의 폴리페놀 함량은 규산염 500배 처리에서 가장 많았다. 꽃은 1,000배 처리에서 가장 높았다. 총 플라보노이드 함량은 꽃이 잎보다 높았으며, 잎은 규산염 500배 처리, 꽃은 키토산 1,000배 처리에서 함량이 가장 많았다. FRAP 활성은 잎의 경우 규산염 500배 처리에서 높았으며, 꽃의 FRAP 활성은 키토산 1,000배에서 좋았으나 처리 간의 차이는 크지 않았다. 자소엽 잎의 ABTS+ 라디칼 저해 활성은 규산염 500배 처리에서 가장 높았으며, 꽃은 경우 무처리에 비하여 자재 처리가 높았으며, 500배보다 1,000배 처리에서 높은 라디칼 저해 활성을 보였다. 이상의 결과, 자소엽 유기자재 처리는 무처리보다 대체로 수량성과 항산화 활성이 높았으나 추가적으로 적정농도 구명 후 경제성 분석이 필요할 것으로 판단된다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.26 no.3
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• pp.191-208
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• 2024

In this study, a hydro-mechanical-damage coupled analysis model was developed to evaluate the structural safety of radioactive waste disposal structures. The Mazars damage model, widely used to model the fracture behavior of brittle materials such as rocks or concrete, was coupled with conventional hydro-mechanical analysis and the developed model was verified via theoretical solutions from literature. To derive the numerical input values for damage-coupled analysis, uniaxial compressive strength and Brazilian tensile strength tests were performed on concrete samples made using the mix ratio of the disposal concrete silo cured under dry and saturated conditions. The input factors derived from the laboratory-scale experiments were applied to a two-dimensional finite element model of the concrete silos at the Wolseong Nuclear Environmental Management Center in Gyeongju and numerical analysis was conducted to analyze the effects of damage consideration, analysis technique, and waste loading conditions. The hydro-mechanical-damage coupled model developed in this study will be applied to the long-term behavior and stability analysis of deep geological repositories for high-level radioactive waste disposal.